Natural shape inflatable undersea structure



KIYOSHIv TSUJI NATURAL SHAPE INFLATABLE UNDERSEA STRUCTURE Filed Feb. 12, 1968 Feb. 24, 1970 INVENTOR.

KIYOSHI TSUJI BY @v1/4^ ATTORNEYS United States Patent O 3,496,730 NATURAL SHAPE INFLATABLE UNDERSEA STRUCTURE Kiyoshi Tsuji, Camarillo, Calif., assignor to the United States of America as represented by the Secretary of the Navy Filed Feb. 12, 1968, Ser. No. 704,743 Int. Cl. B63c 11/00; E04b .7/345; E04g 11/04 U.S. Cl. 61--69 6 Claims ABSTRACT OF THE DISCLOSURE An inflatable undersea structure having a natu-ral configuration when submerged and including loadt-apes -for countering uniaxial stresses. The gas filled structure when submerged creates a buoyant force which is transformed into only uniaxial stress at the wall of the natural shape envelope with no circumferential stress. Load tapes sustain the uniaxial forces and relieve the structure of substantially all stress thus permitting the device to be constructed of relatively weak 'or transparent materials.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

BACKGROUND OF rTHE INVENTION Field of the invention This invention relates in general to undersea structures such as chambers which may be inflatable to provide a protected underwater storage or living space.

Description of the prior art Previously underwater containers have -been of spheroidal or cylindrical configuration which shapes induce biaxial or multiaxial stresses in the wall yof the struct-ure. Accordingly it has been necesary to make such lprior structures of heavy, high strength material precluding the use of lightweight, transparent materials. There is nothing in the prior art concerned with the problem solved by the present invention, namely to provide an underwater structure possessing a -rotationally symmetrical con-figu-ration about a vertical axis thus permitting the structure to be manufactured from a flexible, lightweight transparent material of relatively low strength.

SUMMARY Briefly stated, the present invention in general contemplates an undersea chamber or housing suitable as a storage or inhabitable observation means. The device lincludes an inflatable undersea structure of flexible material Awhich assumes a natural configuration upon which only uniaxial stress forces yare imposed, the latter being opposed by means of load tapes. Thus, with the meridional stress substantialy reduced and with no circumferential stress involved; a strucutre may be made of lightweight, transparent material which assumes and retains a natural shape because of gas under ambient pressure within the structure.

Accordingly it is an object of this invent-ion to provide a submerged inflatable struct-ure with wall or membrane stresses oriented meridionally with zero circumferential stress so that lightweight transparent material-s may be employed on the structure wall to increase visibility and buoyancy.

3,496,730 Patented Feb. 24, 1970 BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a vertical cross section of the present invention when submerged.

FIGURE 2 is Ia view in perspective of the present invention showing the multiple load tapes.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings in detail there is shown in FIG. 1 the submerged envelope indicated generally as 10 with the inflated flexible w-all 12 assumin-g the configuration or shape that would be natural in submerged conditions. The inflated structure is free of circumferential stress when submerged and its buoyant force shown figuratively as 14 is restrained at the perimeter by vertical forces 16.

The natural configuration of the envelope 10 referred to previously depends on the density Iratio of water to air or any other gas or combination of gases such as a helium-oxygen mixture that may be used within the envelope 10. By allowing the gas filled envelope to assume its natural submerged shape, the structure possesses a rotationally symmetrical configuration and is free of circumferential or later stress with only meridional or uniaXial stress remainingin the wall 12.

In order to counteract the me-ridional stress the uniformly spaced load tapes 18 are incorporated into the wall 12 thereby reducing Ithe aforesaid meridional stress to substantially zero. This permits the inflatable envelope 10 to be constructed of relatively low st-rength and transparent materials having excellent visibility or high buoyancy characteristics.

It is pointed out that a natural configuration will be obtained if a fluid other than gas is employed to inflate the submerged envelope 10. Such flu-id may be gasoline or oil, etc. However, a suitable density ratio `of water to fluid must always be maintained.

T'hus it is clear that Ithe structure of the present invention will show increased visibility and ease in handling. Furthermore, it is easily fabricated at 10W cost.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be Iunderstood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

i1. An undersea -walled structure comprising:

an inflatable envelope filled `with a gas and possessing a natural configuration when submerged so that forces acting on the envelope are transformed into a single uniaxial stress; and

means incorporated into said envelope to counter-act said un-iaxial stress acting on said envelope,

lthus relieving the walls of said envelope substantially free of said stress.

2. An Iundersea structure as defined in elaim 1 wherein the means incorporated into said envelope to counteract the uniaxial forces include-s uniformly spaced load tapes.

3. An undersea structure as dened in claim 1 wherein said envelope is constructed of fa lightweight, membrane material having transparent characteristics.

4. A11 undersea structure as dened in claim 1 Wherein said gas is life sustaining.

5. An undersea structure as dened in claim `4 wherein said life sustaining gas comprises ia helium-oxygen mixture.

6. An undersea structure as defined in `claim 1 wherein a uid other than a gas is employed to ll Said inflat-able envelope.

References Cited UNITED STATES PATENTS Caquot 52-2 Helmers 52-2 Schjeldahl et al. -52-2 Cohen et sal. 52-2 X Fraser 52-2 Kwake 52-2 I. KARL BELL, Primary Examiner U.S. C1. XJR. 

